This invention relates to a process and apparatus for fabricating honeycomb material.
Commonly-assigned U.S. Pat. No. 4,885,190 describes a process and machine for making expandable honeycomb material, the contents of which patent are hereby incorporated by reference. The underlying concept is to feed a strip of material from a continuous supply, apply lines of adhesive to the material, cut the strips into desired widths, fold the strips into flat tubular form, and then wind the tubular strips on an annular rack. The adhesive lines are located such that those on top of each tube are located below the bottom of the superposed tube. The resultant assembly of tubes after further processing is heated to activate or soften the glue and compressed to cause the stacked tubes to permanently adhere to one another. With the provision of suitable creases and pleats, an expandable honeycomb structure results of a type that has proved very popular with the public as a window covering. U.S. Pat. Nos. 4,450,027 and 4,849,039 describe other ways of making a similar structure. One aspect of the present invention is to provide an alternative method and apparatus that offers certain advantages.
The honeycomb structure described above offers a window covering with insulating properties if the material used will block or attenuate air flow. If the material is transparent, it will allow light passage; if opaque, it will block light. But the resultant structure cannot control the passage of light in the same sense that a conventional venetian blind allows a user by tilting the slats to control the passage of light through a window into a room.
U.S. Pat. No. 3,384,519 describes a honeycomb structure that is capable of controlling the light passing through. It is made up of transparent cloth sheets interconnected by cloth strips functioning as slats. By making the cloth strips opaque, light will be blocked in one position of the cloth sheets when the strips lie flat and abut or overlap, and light can pass in another position of the cloth sheets when the strips extend in parallel planes. However, the method and apparatus described in this patent for making this structure have certain disadvantages. Another aspect of the present invention provides an alternative method and apparatus that provides certain advantages.
An object of the invention is a novel apparatus for the fabrication of expandable honeycomb structures of the type comprising superposed adhered tubular strips.
Another object of the invention is a novel process and apparatus for the fabrication of expandable honeycomb structures of the type comprising opposed material sheets interconnected by material strips.
A further object is a honeycomb structure and apparatus for making it that is relatively simple and capable of low cost manufacture.
In accordance with a first aspect of the invention, a continuous pre-creased and tubularly-folded strip is passed through an adhesive applicator to form two adhesive lines along the opposed edges of the folded tube. This intermediate product is then processed through a synchronous shearing device or cutter which severs the continuous folded tube into predetermined lengths, which then enter the nip of a strip feeder operating at a much higher speed. The cut tubes are thus accelerated into a stacker, in which they are then pushed or dropped individually down through a bottom opening into a holder, with each next the being stacked on top of the previous tube, or the tubes conveyed away for downstream stacking. The resultant stack of tubes can then be processed as in the referenced patents, by activating the adhesive lines to cause the tubes to adhere to one another to form a unitary structure especially suited for use as a window covering. Alternatively, the conveyed strips can be cut to size, stacked, and adhered to form the unitary structure.
A feature of this aspect of the invention is to accelerate the cut tube to the stacker. This allows the time needed for the tube to reach its final stacking position and be discharged before the next tube arrives. As a result, the processing of the continuous strip can be uninterrupted, and a higher production rate of the finished product is possible.
In accordance with a second aspect of the invention, at least two webs or sheets of material are continuously fed in a downstream direction. These first and second webs will serve as the outer sheets of a honeycomb construction of a type capable of controlling light or air. A middle or third web is provided which can be slit into multiple strips which continue to feed together with the first and second webs in a downstream direction. Lines of adhesive are applied to the webs or to the strips. The adhesive lines are located such that corresponding outer edges of each strip can be respectively adhered to the first and second webs. When the adhesive lines are activated and the webs with intervening strips compressed, a honeycomb structure results that, with opaque strips and transparent outer webs, is capable of controlling the passage of light or air.
A feature of this aspect of the invention is that a surprising number of different structures can be produced with only minor changes in the processing. Some of these structures are especially suited for use as window coverings.
In accordance with a third aspect of the invention, by means of a process which is a variation of that described in connection with the second aspect of the invention, a honeycomb structure results that is not foldable or expandable and that is useful as a low-weight, low-cost insulating barrier. In particular, which the proper location of the strips between the webs, and the provision of additional webs, the resulting sub-assembly when opened presents an array of hexagonal cells. By slitting this sub-assembly into narrow sections, and then bonding material sheets on opposite sides of the open ended cells, the cells are closed forming a reasonably good barrier to the flow of heat. This application will have other uses besides window coverings.
Other objects and advantages of the invention will be apparent from the detailed description that follows of several embodiments in accordance with the different aspects of this invention, which should be taken in conjunction with the accompanying drawings.